Add Vary: Accept header

Author: dmitrizagidulin

lib/create-app.js

@@ -120,8 +120,8 @@ function initHeaders (app) {
   app.use(corsSettings)
 
   app.use((req, res, next) => {
-    // Set X-Powered-By
     res.set('X-Powered-By', 'solid-server')
+    res.set('Vary', 'Accept') // Cors lib adds Vary: Origin automatically
     // Set default Allow methods
     res.set('Allow', 'OPTIONS, HEAD, GET, PATCH, POST, PUT, DELETE')
     next()